Pointer - funcao que recebe um array de point |
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// Apesar de abaixo apresentar uma rotina para formatar strings // é interessante notar a forma como passa o parametro array of pointer // e como o mesmo é detectado se é integer, string, etc...
I have found this unit quite useful, but there may be a problem with the %s tag since its use has generated errors on occasion.
unit Scanf;
interface uses SysUtils;
type EFormatError = class(ExCeption);
function Sscanf(const s: string; const fmt: string; const Pointers: array of Pointer): Integer; implementation
{ Sscanf parses an input string. The parameters ... s - input string to parse fmt - 'C' scanf-like format string to control parsing %d - convert a Long Integer %f - convert an Extended Float %s - convert a string (delimited by spaces) other char - increment s pointer past "other char" space - does nothing Pointers - array of pointers to have values assigned
result - number of variables actually assigned
for example with ... Sscanf('Name. Bill Time. 7:32.77 Age. 8', '. %s . %d:%f . %d', [@Name, @hrs, @min, @age]);
You get ... Name = Bill hrs = 7 min = 32.77 age = 8 }
function Sscanf(const s: string; const fmt: string; const Pointers: array of Pointer): Integer; var i, j, n, m: integer; s1: string; L: LongInt; X: Extended;
function GetInt: Integer; begin s1 := ''; while (s[n] = ' ') and (Length(s) > n) do inc(n); while (s[n] in ['0'..'9', '+', '-']) and (Length(s) >= n) do begin s1 := s1 + s[n]; inc(n); end; Result := Length(s1); end;
function GetFloat: Integer; begin s1 := ''; while (s[n] = ' ') and (Length(s) > n) do inc(n); while (s[n] in ['0'..'9', '+', '-', '.', 'e', 'E']) and (Length(s) >= n) do begin s1 := s1 + s[n]; inc(n); end; Result := Length(s1); end;
function GetString: Integer; begin s1 := ''; while (s[n] = ' ') and (Length(s) > n) do inc(n); while (s[n] <> ' ') and (Length(s) >= n) do begin s1 := s1 + s[n]; inc(n); end; Result := Length(s1); end;
function ScanStr(c: Char): Boolean; begin while (s[n] <> c) and (Length(s) > n) do inc(n); inc(n);
if (n <= Length(s)) then Result := True else Result := False; end;
function GetFmt: Integer; begin Result := -1;
while (TRUE) do begin while (fmt[m] = ' ') and (Length(fmt) > m) do inc(m); if (m >= Length(fmt)) then break;
if (fmt[m] = '%') then begin inc(m); case fmt[m] of 'd': Result := vtInteger; 'f': Result := vtExtended; 's': Result := vtString; end; inc(m); break; end;
if (ScanStr(fmt[m]) = False) then break; inc(m); end; end;
begin n := 1; m := 1; Result := 0;
for i := 0 to High(Pointers) do begin j := GetFmt;
case j of vtInteger: begin if GetInt > 0 then begin L := StrToInt(s1); Move(L, Pointers[i]^, SizeOf(LongInt)); inc(Result); end else break; end;
vtExtended: begin if GetFloat > 0 then begin X := StrToFloat(s1); Move(X, Pointers[i]^, SizeOf(Extended)); inc(Result); end else break; end;
vtString: begin if GetString > 0 then begin Move(s1, Pointers[i]^, Length(s1) + 1); inc(Result); end else break; end; else break; end; end; end;
end. |